(a $21,313, or 19.9%, overspend). It was the most expensive Republic serial of 1937 and the most expensive of all Republic serials until the release of The Lone Ranger in 1938. It was filmed between 10 June and 15 July 1937. The serial's production number was 422. Director William Witney met his first wife, Maxine Doyle, while working on this serial. Stunts Earle D. Bunn Yakima Canutt Loren Riebe Duke Taylor Special effects The serial's special effects were created by Jack Coyle and the Lydecker brothers. Release Theatrical SOS Coast Guard'''s official release date is 28 August 1937, although this is actually the date the sixth chapter was made available to film exchanges. A 71-minute feature film version, created by editing the serial footage together with some additional scenes shot during the serial's production, including a new shot featuring Bela Lugosi, was released on 16 April 1942. The new scenes involved a substantial plot alteration to feature a made-up chemical, called arnatite, as a deadly explosive in and of itself, and other dialogue to cover continuity gaps arising from the editing. Chapter titles Disaster at Sea (30 min 3s)Barrage of Death (19 min 46s)The Gas Chamber (18 min 40s)The Fatal Shaft (19 min 35s)The Mystery Ship (18 min 31s)Deadly Cargo (18 min 4s)Undersea Terror (15 min 46s)The Crash! (16 min 34s)Wolves at Bay (15 min 56s)The Acid Trail (16 min 58s)The Sea Battle (17 min 12s)The Deadly Circle (17 min 3s)Source: CliffhangersDisaster at Sea: Terry and Thorg fight on a Tramp steamer as it sinks.Barrage of Death: Terry is tied up aboard a boat as the Coast guard open fire unawares.The Gas Chamber: Terry and Snapper are trapped in a glass cabinet as the Disintegration Gas melts the room.The Fatal Shaft: A freight elevator crashes down onto Terry.The Mystery Ship: Whilst attempting to shut them down, Terry is caught in a boiler explosion.Deadly Cargo: A water tower, weakened by the Disintegration Gas, collapses on Terry.Undersea Terror: While fighting underwater, Thorg cuts through Terry's air line.The Crash!: The car carrying Terry, Jean and Snapper plunges down a steep slope after Boroff's henchmen shoot out a tyre.Wolves at Bay: Terry, Jean and Snapper are caught inside an exploding warehouse.The Acid Trail: When Terry attempts to rescue Dick Norman from a burning truck, the brake line melts and it plunges over a cliff into the sea.The Sea Battle:'' Terry is caught by Thorg